Some corrections and additions to the Complete Peerage: Volume 5: Fauconberge (PROPOSED CORRECTIONS)

FAUCONBERGE or FAUCOMBERGE

Volume 5, page 276:
He [Sir Thomas Faucomberge (d. 1407)] m., 1stly, before 17 Nov. 1366, Constance, da. and h., most probably, of John DE FELTON (yr. br. of Sir William DE FELTON, of Edlingham, Northumberland).(g)
Note g:
According to Graves, Hist. of Cleveland, p. 48, Constance was sister of Sir William de Felton, but this is impossible. It appears, however, to be certain from her will that she belonged to the family of the Feltons of Edlingham, who are, moreover, known to have been cousins of the King, and there seems little doubt that she was the Constance who is mentioned as da. of this John de Felton (Coram Rege, Trin. 43 Edw. III, m. 22).
Page 278:
On 14 Mar. 1389/90 the King granted the petition of Constance, wife of Thomas Faucomberge kt. (que de parentela nostra existit), ...

The marriage of Thomas and Constance took place by 21 Sept 1354 (when Thomas was aged 9) [Calendar of Inquisitions Post Mortem, vol. 11, no 330]. It is very unlikely that Thomas's wife Constance is the same Constance, daughter of John de Felton referred to in the account above, who was mentioned in a charter dated in or before 1328 [Calendar of Inquisitions Post Mortem, vol. 12, p. 179]. Moreover, the John de Felton later associated with Thomas and Constance is clearly not the brother of William de Felton of Edlingham (d. 1358), but his son John (d. 1396), by his second wife Isabel, daughter of Duncan, Earl of Fife (see Felton, vol. 5, p. 294); and it is through Isabel that the Feltons of Edlingham were cousins of Edward III. Constance's will does not appear to contain any clear evidence that she was a Felton, although she does name as executors Edmund Hastings and his wife Elizabeth, and Elizabeth was a daughter of John de Felton (d. 1396).

The evidence just mentioned, together with chronology, would all suggest that Constance was a daughter of William de Felton (d. 1358) by his second wife Isabel of Fife. However, doubt is cast on this solution by the Northamptonshire inquisition post mortem, taken in 1403 after the death of John de Felton, son of John de Felton (d. 1396), which returned as his heir of the whole blood John, the son of Walter Faucomberge, knight, [of Bilton] and Joan, late his wife, the aunt of the deceased [Calendar of Inquisitions Post Mortem, vol. 18, no 755]. If Constance had been a daughter of William and Isabel, her son John should also have been named as a coheir (although the identity of the coheirs seems to have been of no practical importance, as the Felton lands passed to the half-sister of the deceased).

[Much of the material relevant to this problem was supplied by Rosie Bevan; Douglas Richardson made further contributions.]